Acid and pH in Wine

California’s finest wine growing regions are blessed with warm days, cool nights and very little precipitation during the critical weeks prior to harvest.  While other highly acclaimed national and international appellations battle frost, cold or rain during their growing seasons, California often struggles with a very different problem … excessive heat.  Though plenty of sunshine and high temperatures are quite effective in ripening fruit quickly, rapid maturation diminishes flavor development and the all-important retention of natural acidity.

California vintages with the highest degree of structural integrity are those with moderately cool and steady growing conditions.  Such vintages typically produce wines with generous fruit profiles, high natural acidity and relatively low pH.  As harvest approaches, we monitor flavor development, sugar levels, acid and pH values daily, as missing harvest by even one day can result in compromises to the desired balance of the finished wine.

At Alysian, we strive to produce fully flavored, elegantly styled wines with moderate alcohols, generous acidity and low pH.  With warmer conditions in California, winemakers often struggle with escalating sugars and lagging flavor development.  Waiting for maximum flavor can often lead to “ripe” wines with excessive alcohol, low acidity and high pH.  One of my biggest challenges producing wines in “our style” is the identification of vineyards capable of achieving flavor maturity at lower sugar levels.  After decades of work in the Russian River Valley, (observing soil, micro-climate and viticultural variations) we have been quite successful with the identification of such vineyards.

There are many advantages to producing structurally correct, balanced wines.  On a sensory level, wines with excessive alcohol can produce undesirable “heat” in the finish, while low acid/high pH wines can be flat and lack freshness.  Conversely, wines with lower alcohols and generous acidity are more likely to be crisp, vibrant and refreshing.  Though pH values are not directly related to total acidity, wines with higher acidity generally exhibit lower pH values.  For those looking to produce stable, age-worthy wines, careful attention to pH is critical.  Lower pH juices ferment cleaner, produce more favorable flavoring and coloring compounds and offer increased microbial stability by inhibiting bacterial growth.  Furthermore, less sulfur is required to preserve and protect low pH wines from oxidation and spoilage organisms.  Consider the average red wine in California (finished pH value of 3.6) requires 50% more free sulfur than our average finished red wine at Alysian (3.4 pH) to offer equal protection.  Yet another tremendous advantage of producing wines with statistical and structural integrity.

Gary Farrell, winemaker